scholarly journals Nonlinear Analysis of Cable Net Structures

2021 ◽  
Vol 9 (2) ◽  
pp. 142-156
Author(s):  
Daniel Ricardo Salinas Guayacundo ◽  
Edgardo Alejandro Marmolejo Otero
Keyword(s):  
Nonlinear Analysis ◽  
Static Loading ◽  
Geometric Analysis ◽  
Three Dimensional ◽  
Analytical Form ◽  
Theoretical Background ◽  
Form Finding ◽  
Critical Data ◽  
Cable Forces ◽  
Stability Of The Solution

Objective: To present a methodology for implementing in MathCAD, a based on force densities for analytical form finding to three-dimensional cable net structures subjected to static loading. It is desired that the routines present a stability of the solution algorithm and fast convergence. Methodology: Theoretical background of the cable net structures behavior and FDM are first introduced. Then, a series of MathCAD routines are created to perform the nonlinear analysis of cable net structures. Finally, a well-documented cable net structure example found in the literature, and the results from a cable net software are used as a way to validate the output results provided by the created MathCAD routines. Results: The simulation results show that the proposed methodology implemented in MathCAD can accurately estimate the free nodes displacements and cable forces of 3D cable net structures subjected to vertical and horizontal static loading. Conclusions: This paper has demostrated that the propossed methodology is consistent when comparing with the results given in the reference paper and the used software. Stability of the algorithms is controlled and no numerical issues was presented during the analyzed examples thus, divergence complications were not found. The routines provided a clear way to visualize the assumptions, methods, and critical data obtained in the geometric analysis of cable net structures helping to overcome the inherit limitations of commercial packages.

scholarly journals An Alternative Method for Calculating the Eddy Current Loss in the Sleeve of a Sealless Pump

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 78
Author(s):  
Tomislav Strinić ◽  
Bianca Wex ◽  
Gerald Jungmayr ◽  
Thomas Stallinger ◽  
Jörg Frevert ◽  
...  
Keyword(s):  
Eddy Current ◽  
Three Dimensional ◽  
Eddy Current Loss ◽  
Theoretical Background ◽  
Air Gap ◽  
Magnetic Flux Density ◽  
Pump Impeller ◽  
Current Loss ◽  
Faraday’S Law ◽  
Transient Simulations

A sealless pump, also known as a wet rotor pump or a canned pump, requires a stationary sleeve in the air gap to protect the stator from a medium that flows around the rotor and the pump impeller. Since the sleeve is typically made from a non-magnetic electrically conductive material, the time-varying magnetic flux density in the air gap creates an eddy current loss in the sleeve. Precise assessment of this loss is crucial for the design of the pump. This paper presents a method for calculating the eddy current loss in such sleeves by using only a two-dimensional (2D) finite element method (FEM) solver. The basic idea is to use the similar structure of Ampère’s circuital law and Faraday’s law of induction to solve eddy current problems with a magnetostatic solver. The theoretical background behind the proposed method is explained and applied to the sleeve of a sealless pump. Finally, the results obtained by a 2D FEM approach are verified by three-dimensional FEM transient simulations.

scholarly journals The on-axis magnetic well and Mercier's criterion for arbitrary stellarator geometries

2021 ◽  
Vol 87 (2) ◽  
Author(s):  
P. Kim ◽  
R. Jorge ◽  
W. Dorland
Keyword(s):  
Magnetic Field ◽  
Original Work ◽  
Three Dimensional ◽  
Radial Distance ◽  
Analytical Form ◽  
One Dimensional ◽  
Modern Notation ◽  
Magnetic Well ◽  
First Time ◽  
Dimensional Integral

A simplified analytical form of the on-axis magnetic well and Mercier's criterion for interchange instabilities for arbitrary three-dimensional magnetic field geometries is derived. For this purpose, a near-axis expansion based on a direct coordinate approach is used by expressing the toroidal magnetic flux in terms of powers of the radial distance to the magnetic axis. For the first time, the magnetic well and Mercier's criterion are then written as a one-dimensional integral with respect to the axis arclength. When compared with the original work of Mercier, the derivation here is presented using modern notation and in a more streamlined manner that highlights essential steps. Finally, these expressions are verified numerically using several quasisymmetric and non-quasisymmetric stellarator configurations including Wendelstein 7-X.

Elastic solution of a polyhedral particle with a polynomial eigenstrain and particle discretization

2021 ◽  
pp. 1-35
Author(s):  
Chunlin Wu ◽  
Liangliang Zhang ◽  
Huiming Yin
Keyword(s):  
Taylor Series ◽  
Three Dimensional ◽  
Stress Singularity ◽  
Elastic Field ◽  
Analytical Form ◽  
Tetrahedral Elements ◽  
Equivalent Inclusion Method ◽  
Equivalent Inclusion ◽  
Eshelby’S Tensor ◽  
Domain Discretization

Abstract The paper extends the recent work (JAM, 88, 061002, 2021) of the Eshelby's tensors for polynomial eigenstrains from a two dimensional (2D) to three dimensional (3D) domain, which provides the solution to the elastic field with continuously distributed eigenstrain on a polyhedral inclusion approximated by the Taylor series of polynomials. Similarly, the polynomial eigenstrain is expanded at the centroid of the polyhedral inclusion with uniform, linear and quadratic order terms, which provides tailorable accuracy of the elastic solutions of polyhedral inhomogeneity by using Eshelby's equivalent inclusion method. However, for both 2D and 3D cases, the stress distribution in the inhomogeneity exhibits a certain discrepancy from the finite element results at the neighborhood of the vertices due to the singularity of Eshelby's tensors, which makes it inaccurate to use the Taylor series of polynomials at the centroid to catch the eigenstrain at the vertices. This paper formulates the domain discretization with tetrahedral elements to accurately solve for eigenstrain distribution and predict the stress field. With the eigenstrain determined at each node, the elastic field can be predicted with the closed-form domain integral of Green's function. The parametric analysis shows the performance difference between the polynomial eigenstrain by the Taylor expansion at the centroid and the 𝐶0 continuous eigenstrain by particle discretization. Because the stress singularity is evaluated by the analytical form of the Eshelby's tensor, the elastic analysis is robust, stable and efficient.

Dynamic Nonlinear Analysis of an Hybrid Base Isolation System with Viscous Dampers and Friction Sliders in Parallel

2012 ◽  
Vol 234 ◽  
pp. 96-101 ◽  
Author(s):  
Donato Cancellara ◽  
Fabio de Angelis
Keyword(s):  
Nonlinear Analysis ◽  
Base Isolation ◽  
Three Dimensional ◽  
Time History ◽  
Seismic Action ◽  
Viscous Dampers ◽  
Isolation System ◽  
Fixed Base ◽  
Base Isolation System ◽  
Dynamic Nonlinear Analysis

In the present work we have analyzed a particular base isolation system for the seismic protection of a multi-storey reinforced concrete (RC) building. The viscous dampers and friction sliders are the devices adopted in parallel for realizing the base isolation system. The base isolation structure has been designed and verified according to European seismic code EC8 and by considering for the friction sliders the influence of the sliding velocity on the value of the friction coefficient. A dynamic nonlinear analysis for a three-dimensional base isolated structure has been performed. Recorded accelerograms for bi-directional ground motions have been used which comply with the requirements imposed by EC8 for the representation of a seismic action in a time history analysis. In this paper a comparative analysis is presented between the base isolated structure with the described hybrid base isolation system and the traditional fixed base structure.

scholarly journals Comparative Analysis of Static Loading Performance of Rigid and Flexible Road Wheel based on Finite Element Method

2020 ◽  
Vol 70 (1) ◽  
pp. 41-46
Author(s):  
Yaoji Deng ◽  
Youqun Zhao ◽  
Mingmin Zhu ◽  
Zhen Xiao ◽  
Qiuwei Wang
Keyword(s):  
Finite Element ◽  
Finite Element Model ◽  
Static Loading ◽  
Maximum Stress ◽  
Three Dimensional ◽  
Element Model ◽  
Vertical Load ◽  
New Type ◽  
Stress And Deformation ◽  
Nonlinear Finite Element Model

To overcome the shortcomings of traditional rigid road wheel, such as poor damping effect and low load-bearing efficiency, a new type of flexible road wheel, having a unique suspension-bearing mode, was introduced. The three-dimensional nonlinear finite element model of rigid and flexible road wheel, considering the triple nonlinear characteristics of geometry, material and contact, is established for numerical investigation of static loading performance. The accuracy of the finite element model of the rigid and flexible road wheel is verified by static loading experiment. The static loading performance of the rigid and flexible road wheels is numerically analyzed. The influence of vertical load on maximum stress and deformation of the rigid and flexible wheels is also studied. The results show that the contact pressure uniformity of the flexible road wheel is better than that of the rigid road wheel under the static vertical load, but the maximum stress and deformation of the flexible road wheel are greater than that of the rigid road wheel. However, this problem can be solved by increasing the number of hinge sets and optimising the joints. The research results provide theoretical basis for replacing rigid road wheel with flexible road wheel, and also provide reference for structural optimisation of flexible road wheel.

Three-dimensional nonlinear analysis of drill string structure in annulus

1994 ◽  
Vol 15 (3) ◽  
pp. 275-290 ◽  
Author(s):  
Liu Yan-qiang ◽  
Lü Ying-min
Keyword(s):  
Nonlinear Analysis ◽  
Three Dimensional ◽  
Drill String ◽  
String Structure

scholarly journals Three-dimensional light sculpting using a geometric analysis

2019 ◽  
Vol 431 ◽  
pp. 210-215 ◽  
Author(s):  
Andrew Bañas ◽  
Einstom Engay ◽  
Ada-Ioana Bunea ◽  
Stephen Daedalus Separa ◽  
Jesper Glückstad
Keyword(s):  
Geometric Analysis ◽  
Three Dimensional

Understanding and Conserving Fortified and Difficult to Access Architectures through Digital Survey

2015 ◽  
pp. 654-685 ◽  
Author(s):  
Mariateresa Galizia ◽  
Alessandro Lo Faro ◽  
Cettina Santagati
Keyword(s):  
Geometric Analysis ◽  
Three Dimensional ◽  
Second Step ◽  
Cylindrical Shape ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Unique Case ◽  
Virtual Reconstruction ◽  
A Site ◽  
Digital Survey

In this paper we propose a multidisciplinary approach concerning the tower of Mongialino in Mineo (Sicily), which is a unique case in Sicily of a cylindrical tower with an inner cylindrical nucleus. The vestiges of the dungeon rise on a rock promontory that dominates the valley of Margi, a site that has great landscape and territorial value. The building is affected by important collapses and lesions, and urgently requires a safeguard intervention that requires a deep knowledge and understanding of the construction. The first step of this process is a suitable documentation and representation of the cylindrical shape and its towering position. The peculiarity of the object requires the integrated use of current technologies of surveying able to provide a metrically-accurate three-dimensional model. The second step is the critic reading of the technological, typological and material elements that constitutes the constructive apparatus of the building (masonry, ribs, ring-like vault), and the geometric analysis addressed at the virtual reconstruction of the original shape.

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